This invention relates to a coupler assembly and more particularly to a light transport coupler assembly for data communications.
Fiber optic cable data communication systems commonly require a coupler device which links optical data signals from a light emitting diode (LED) into a fiber optic cable. The fiber optic cable will then transmit the LED communication signals to external interfaces. The stronger the light signal within the fiber optic cable, the greater the potential for more interfaces and in-line connections with the cable (the more nodes within the system).
A LED consists of a metallic frame and a die secured to the frame. The die is actually a silicon chip. The metallic frame carries a current and produces a voltage differential across the silicon chip. As a result, the chip glows, emitting light. A clear material, commonly plastic, encases a portion of the metallic frame and the die, thereby protecting the die to frame connection. The outer surface of the plastic insulator over the die is formed into an aspheric lens. The asperic lens focuses some of the light emitted from the die onto an input face of the fiber optic cable. Only the incident rays within the acceptance angle of the fiber optic cable are transmitted. The remaining light emitted from the die is lost due to reflection within the insulator or refraction into air. The loss of this light hinders the strength of the fiber optic cable signal.
The invention provides a coupler assembly having an emitting light face, an aspheric lens, a reflective surface and an input face of a fiber optic cable, positioned along a centerline. The integral lens has a base located forward of the light source and a dome located forward of the base. The aspheric lens is further circumvented by the reflective surface.
The dome has an end surface and an apex separated by a first length along the centerline. The apex is located forward of the end surface. The base has a first end and a second end separated by a second length along the centerline. The second end is located forward of the first end. The emitting face is located at a distance less than the first length but greater than second length taken from the end surface extending rearward.
The reflective surface has an outer edge located forward of an inner edge. The reflective surface expands radially and elliptically outward from the inner edge to the outer edge. The inner edge is axially aligned to the first end of the base and the outer edge is axially aligned to the apex of the dome.
A feature of the invention is attributable to the base wherein the reflected rays of the prior art are refracted through the base. This refraction enhances the percentage of rays which become incident to the input face of the fiber optic cable thereby increasing signal strength.
Another feature of the invention is attributable to the reflective surface wherein the refracted rays from the base are reflected upon the surface. Once reflected the angle of the rays are such where the rays are incident to the input face. The input strength of the data communication signal is thereby increased further.
These and other objects, features and advantages of the invention will become more apparent from the following description of a preferred embodiment taken in conjunction with the accompanying drawing.